scholarly journals The Effect of Foliar Selenium (Se) Treatment on Growth, Photosynthesis, and Oxidative-Nitrosative Signalling of Stevia rebaudiana Leaves

Antioxidants ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 72
Author(s):  
Péter Borbély ◽  
Árpád Molnár ◽  
Emil Valyon ◽  
Attila Ördög ◽  
Klára Horváth-Boros ◽  
...  

Selenium (Se) enrichment of Stevia rebaudiana Bertoni can serve a dual purpose, on the one hand to increase plant biomass and stress tolerance and on the other hand to produce Se fortified plant-based food. Foliar Se spraying (0, 6, 8, 10 mg/L selenate, 14 days) of Stevia plantlets resulted in slightly decreased stevioside and rebaudioside A concentrations, and it also caused significant increment in stem elongation, leaf number, and Se content, suggesting that foliar Se supplementation can be used as a biofortifying approach. Furthermore, Se slightly limited photosynthetic CO2 assimilation (AN, gsw, Ci/Ca), but exerted no significant effect on chlorophyll, carotenoid contents and on parameters associated with photosystem II (PSII) activity (FV/FM, F0, Y(NO)), indicating that Se causes no photodamage in PSII. Further results indicate that Se is able to activate PSI-cyclic electron flow independent protection mechanisms of the photosynthetic apparatus of Stevia plants. The applied Se activated superoxide dismutase (SOD) isoenzymes (MnSOD1, FeSOD1, FeSOD2, Cu/ZnSOD1, Cu/ZnSOD2) and down-regulated NADPH oxidase suggesting the Se-induced limitation of superoxide anion levels and consequent oxidative signalling in Stevia leaves. Additionally, the decrease in S-nitrosoglutathione reductase protein abundance and the intensification of protein tyrosine nitration indicate Se-triggered nitrosative signalling. Collectively, these results suggest that Se supplementation alters Stevia shoot morphology without significantly affecting biomass yield and photosynthesis, but increasing Se content and performing antioxidant effects, which indicates that foliar application of Se may be a promising method in Stevia cultivation.

2020 ◽  
Vol 47 (12) ◽  
pp. 1083
Author(s):  
Nasibeh Tavakoli Hasanaklou ◽  
Mohammad Sedghi ◽  
Foad Moradi ◽  
Ali Ebadi Khazineh Ghadim ◽  
Sodabeh Jahanbakhsh Ghodehkahriz

Stevia is a herbaceous plant containing non-sugar sweeteners that could be regarded as a successor to sugar for diabetics. However, there are some problems with the cultivation of stevia, especially in the greenhouse, including unbranching and low sweetening agents. To overcome this issue, an experiment was designed to increase not only the branching and leaf production but also the sweetness. Therefore, a novel strategy using abscisic acid (0, 50, 100, 150 μM), its inhibitor, i.e. fluridone (0, 50, 100, 150 μM) and decapitation of plant apical meristems was applied. Results showed that when stevia was decapitated, dormant buds responded to the application of abscisic acid and fluridone. Under these conditions, axillary buds were developed to branches. As well leaf, total dry weight, soluble sugars and steviol glycosides (SGs) were significantly increased. In addition, the interaction of abscisic acid (50 and 100 μM) and fluridone (50 μM) had the highest positive effects on plant growth and steviol glycosides production rather than their sole applications. Results also indicated that decapitation removed a terminal dominance over a limited period of time and the terminal dominance was re-established with the growth of the terminal branches, whereas the influence of 50 µM fluridone on stevia was long term and the number of shoots was greater. Since stevia is a costly sweetener, the results of this study could be used in greenhouses, where the cultivation of stevia seems to be reasonable in terms of economic aspects.


Planta Medica ◽  
2013 ◽  
Vol 79 (13) ◽  
Author(s):  
LF Ceole ◽  
SS Lopes ◽  
AJ Oliveira ◽  
BP Dias Filho ◽  
CV Nakamura ◽  
...  

Author(s):  
М. В. Ромашова ◽  
Е. Н. Барсукова

Изучены элементы технологического процесса выращивания стевии ( Stevia rebaudiana Bertoni) в открытом грунте в погодно-климатических условиях Приморского края; выявлен оптимальный рельеф почвы и эффективный возраст рассады стевии; рассчитана экономическая эффективность выращивания стевии в открытом грунте.


2020 ◽  
Vol 2 (1) ◽  
pp. 11-20
Author(s):  
Meta Kartika Untari ◽  
Ganet Elo Pramukantoro

Hypercholesterolemia is a state of increased levels of LDL (Low Density Lipoprotein) and total cholesterol in the plasma. Stevia leaves have benefits to overcome hypercholesterolemia. The aimed of this study was to obtain ethanol extracts of Stevia rebaudiana Bertoni leaves which have activity to reduce total cholesterol levels in patients with hypercholesterolemia with effective doses. The method that will be carried out to achieve this goal was to make extracts by maceration of Stevia rebaudiana Bertoni leaf powder using a water solvent for 5 days. Testing antihypercholesterolemia activity by giving treatment to 20 male white rats. Rats were divided into 5 treatment groups. Group I was negative control, II was simvastatin control, III extract was 30 mg / 200 g BW, IV extract was 60 mg / 200 g BW, V extract was 120 mg / 200 g BW. The mice were induced by propylthiouracil 12.5 mg / day and high-fat feed for 21 days, after which the rats were given the test for 14 days. Cholesterol levels were measured on days 0, 21st and 28th. The method of determining cholesterol levels uses the Easy Touch tool. On the 35th day, a total cholesterol level was examined and data analysis was performed. The results showed that the ethanol extract of stevia leaves had antihypercholesterolemia activity, extract dose of 30 mg / 200 g BW had antihypercholesterolemia activity which was equivalent to simvastatin.


Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 820
Author(s):  
Clara Azzam ◽  
Sudad Al-Taweel ◽  
Ranya Abdel-Aziz ◽  
Karim Rabea ◽  
Alaa Abou-Sreea ◽  
...  

Stevia rebaudiana Bertoni is a little bush, which is cultivated on a large scale in many countries for medicinal purposes and used as a natural sweetener in food products. The present work aims to conduct a protocol for stevia propagation in vitro to produce and introduce Stevia rebaudiana plants as a new sweetener crop to Egyptian agriculture. To efficiently maximize its propagation, it is important to study the influence of stress factors on the growth and development of Stevia rebaudiana grown in vitro. Two stevia varieties were investigated (Sugar High A3 and Spanti) against salt stress. Leaves were used as the source of explants for callus initiation, regeneration, multiplication and rooting. Some stress-related traits, i.e., photosynthetic pigments, proline contents, and enzyme activity for peroxidase (POD), polyphenol oxidase (PPO), and malate dehydrogenase (MDH) were studied. Murashig and Skoog (MS) medium was supplemented with four NaCl concentrations: 500, 1000, 2000, and 3000 mgL−1, while a salt-free medium was used as the control. The data revealed that salinity negatively affected all studied characters: the number of surviving calli, regeneration%, shoot length, the number of multiple shoots, number of leaf plantlets−1, number of root plantlets−1, and root length. The data also revealed that Sugar High A3 is more tolerant than Spanti. The total chlorophyll content decreased gradually with increasing NaCl concentration. However, the opposite was true for proline content. Isozyme’s fractionation exhibited high levels of variability among the two varieties. Various biochemical parameters associated with salt tolerance were detected in POD. Namely, POD4, POD6, POD 9 at an Rf of 0.34, 0.57, and 0.91 in the Sugar High A3 variety under high salt concentration conditions, as well as POD 10 at an Rf of 0.98 in both varieties under high salt concentrations. In addition, the overexpression of POD 5 and POD 10 at Rf 0.52 and 0.83 was found in both varieties at high NaCl concentrations. Biochemical parameters associated with salt tolerance were detected in PPO (PPO1, PPO2 and PPO4 at an Rf of 0.38, 0.42 and 0.62 in the Sugar High A3 variety under high salt concentrations) and MDH (MDH 3 at an Rf of 0.40 in both varieties at high salt concentrations). Therefore, these could be considered as important biochemical markers associated with salt tolerance and could be applied in stevia breeding programs (marker-assisted selection). This investigation recommends stevia variety Sugar High A3 to be cultivated under salt conditions.


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